The ATLAS experiment at the LHC

Welcome to the ATLAS group at the University of Victoria


The Large Hadron Collider (LHC), located at the CERN laboratory near Geneva, provides the highest energy proton-proton collisions, currently at a center of mass energy of 13 TeV.  The ATLAS Collaboration constructed and operates a large detector, located on the LHC ring, to detect and record the products of the proton collisions.  The LHC and the ATLAS detector together form the most powerful microscope ever built, allowing scientists to explore space and time, and the fundamental laws of nature, to unprecedented levels. 

Central goals of the ATLAS experiment are the search for the Higgs boson, a particle predicted to be linked to the mystery of the origin of mass at a fundamental level, and the search for physics beyond the Standard Model of particle physics, such as supersymmetry or extra spatial dimensions.  On July 4th 2012 the ATLAS Collaboration announced the discovery of a new particle, a boson consistent with the sought-after Higgs boson; on October 8th 2013 the Nobel Prize in Physics was awarded to Prof. Englert and Prof. Higgs.

VISPA scientists are founding members of the ATLAS Collaboration, and participated in the design and construction of the ATLAS detector.  The UVic group is currently composed of over 25 scientists, including students, research associates, technicians, computer experts, engineers and physics professors.  Since 1992, the ATLAS project at UVic provides unique opportunities for the training of highly qualified personnel; many former UVic-ATLAS members now hold permanent positions in top institutions in Canada and abroad.  The VISPA-ATLAS team benefits from its close relation with TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics. 

Dr. Rob McPherson, professor of Physics at UVic and Research Scientist at the Institute of Particle Physics of Canada, was Deputy Spokesperson of the ATLAS Collaboration for two years until end of February 2017.

The ATLAS Detector

UVic-ATLAS Activities

The UVic-ATLAS group is engaged in many ATLAS activities.  Click below to expand.

Data Analyses

UVic scientists have contributed to ATLAS data analyses since the first LHC collisions in 2010, and are currently involved in a variaty of data analyses.

Recent published papers with important contributions from UVic scientists:

Public notes

Work in progress:

  • Measurement of triple gauge boson couplings.
  • Search for new light gauge bosons in Higgs boson decays to four-lepton final states, full Run 2 dataset
  • Search for an invisibly decaying Higgs boson or dark matter candidates produced in association with a Z boson in pp collisions at √s = 13 TeV with the ATLAS detector, full Run 2 dataset.
  • Search for pair production of gluinos decaying via third generation squarks resulting in a final state with multiple b-jets and two lightest neutralinos
  • Search for dark matter produced in association with a hypothetical scalar boson decaying to W+W−, in the fully hadronic and semi-leptonic final states

Past topics with UVic contributions include:

  • Measurement of the properties of the discovered Higgs boson.
  • Mesaurement of the WZ diboson production cross section, and measurement of the W and Z polarizations in WZ events.
  • Precise measurement of the e+e- and μ+μ- Drell-Yan pairs invariant mass distribution.
  • Precise measurement of the transverse momentum of the Z boson.
  • Search for supersymmetry with third generation squarks.
  • Search for supersymmetry using a Higgs boson in the decay cascade.
  • Search for new massive particles decaying to a pair of top quarks.
  • Search of quark compositeness through the study of the angular distribution of dijet events.
  • Search for long-lived exotic particles.
  • Search for contact interactions in dilepton events.

Detector Operation and Performance

The operation of the ATLAS detector and the assessement and improvement of its performance are critical aspects of the ATLAS program.  Members of the UVic ATLAS group contributions include the following activities:

  • Liquid argon calorimeter
    • Run coordination
    • Data quality 
    • Signal pulse shape studies using pp collision data
  • Missing transverse momentum high level trigger
    • Operation activities 
    • Algorithm development and pileup mitigation
    • Monitoring and performance evaluation
      • "Performance of the ATLAS global transverse-momentum triggers at √s = 8 TeV", ATL-DAQ-PUB-2018-001
      • "Analytical description of missing transverse-momentum trigger rates in ATLAS with 7 and 8 TeV data", ATL-DAQ-PUB-2017-002
    • Performance optimization
      • MET algorithm developent for high pileup running

Detector Upgrades

The ATLAS detector was built in the 1990's, and some of its components need to be upgraded, or replaced, to operate in the higher luminosity environment expected at the LHC for Phase-I Run 3 (2021-2023) and for Phase-II running (2026-2037 and beyond).  UVic is contributing to the following ATLAS upgrade projects:

  • Phase I and II liquid argon calorimeter readout electronics upgrade
  • Phase I new muon small wheel detector

Computing

The High Energy Physics Research Computing Group at the University of Victoria is actively engaged in a variety of projects for the analysis of data from particle physics experiments, including ATLAS.  Areas of expertise include:

  • High-speed networks
  • Management of large scale data storage
  • Virtualization
  • Grid computing
  • Cloud computing

Brief history of Canada and UVic in ATLAS

The ATLAS Collaboration was founded in 1992, and includes the University of Victoria as one of its founding institutes. The UVic-ATLAS group was led by Prof. Michel Lefebvre, and included Prof. Alan Astbury and Prof. Richard Keeler. Prof. Lefebvre was the founding Spokesperson of the ATLAS-Canada Collaboration, founded in 1992 with colleagues from the Université de Montréal.  The UVic-ATLAS group has been growing, and now also includes Dr. Justin Albert, Prof. Robert Kowalewski, Prof. Robert McPherson, Prof. Randy Sobie, and Dr Isabel Trigger (TRIUMF).  Both McPherson and Sobie are Institute of Particle Physics Scientists. Prof. McPherson has been the Principal Investigator of the ATLAS-UVic group from 2003 to 2015, and was Spokesperson of the ATLAS-Canada Collaboration from 2007 to 2015; he was appointed Deputy Spokesperson of the ATLAS Collaboration for two years starting February 2015.  Prof. Lefebvre acted as the Principal Investigator of the ATLAS-UVic group from 2015 to 2018; Prof. McPherson is Principal Inverstigator of the ATLAS-UVic group since April 2018.  The particle physics expertise at UVic goes hand in hand with its close relation with TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics. TRIUMF staff located at UVic played crucial roles in the construction of the ATLAS experiment.

Canadian involvement in ATLAS and the LHC has placed us in a prominent position in the forefront international science project of the decade. In total Canada has invested $70 million of the $8 billion total in equipment that is now a crucial part of the CERN LHC accelerator complex and the ATLAS particle physics experiment. Canadian researchers have received an additional $30 million to fund graduate students, postdoctoral researchers and their research on ATLAS. TRIUMF has provided staff and technical support to make these contributions a reality. As a result of these investments and the resulting scientific and technical expertise Canada is a respected partner at CERN and in the international science community.

No single country could afford to build the $8 billion LHC project on its own. ATLAS has been built by researchers from more than 150 universities and laboratories in 35 countries. 150 Canadian scientists (faculty, lab staff, postdoctoral researchers and graduate students) from eleven institutions across the country work at CERN, alongside 2000 other scientists from every corner of the globe, on the ATLAS experiment. Canada has made important contributions to the LHC, ATLAS and the world-wide computing grid now digesting the ATLAS data.

In 1995 TRIUMF was given the mandate to act as Canada's main connection with CERN. It was provided with $42 million of federal funding over ten years to develop and construct components for the LHC. These projects were completed on time and in budget in close collaboration with Canadian industry. Over 90% of our LHC funding has been spent in Canada. There have been a number of spin-offs from this activity. I.E. Power, Inverpower and Digital Predictive Systems in Ontario gained expertise in high current power supply design and fabrication and have competed successfully for an additional $10M in contracts from major international labs. ALSTOM-Canada, in Tracy, Quebec improved assembly tolerances for LHC magnets benefiting their main business, the fabrication of hydro generators. Canadians were instrumental in the construction of the ATLAS detector. ATLAS construction was supported by a $12 million grant from the Natural Sciences and Engineering Research Council of Canada (NSERC). Canadian contributions to the ATLAS detector were completed on time and on budget, are now installed in the ATLAS experiment where they are currently successfully used to record the LHC collisions. 

When taking data, ATLAS produces several Peta-bytes (millions of Giga-bytes) of data per year. Canada has constructed a Tier1 computing centre at TRIUMF funded by the Canadian Foundation for Innovation (CFI) and the BC Knowledge Development Fund (BCKDF) at the levels of $12 million and $4 million, respectively. The primary role of the Tier1 centre is the processing of raw ATLAS data which will be used by physicists to understand what is going on in the high energy proton collisions. The final analyses will be performed largely on the Tier 2 computing centres located at university sites, funded by the CFI National Platforms Fund. The combined Canadian Tier1 and Tier2 centres give us "made in Canada" physics analysis ability, positioning ourselves to be leaders in extracting ATLAS physics over the coming years.

The UVic-ATLAS group is currently composed of over 25 scientists, including students, research associates, technicians, computer experts, engineers and physics professors. Since 1992, the ATLAS project at UVic provides unique opportunities for the training of highly qualified personnel. Many former UVic-ATLAS members now hold permanent positions in top institutions in Canada and abroad.

The UVic-ATLAS group has made crucial contributions to the design, development and construction of the ATLAS detector since 1992. UVic's contributions focused on detector components, called calorimeters, specialized in the measurement of the energy of particles. The chosen technology features liquid argon as active medium, and makes use of a novel geometrical design optimized in part at UVic. From 1992 to 2004 UVic scientists participated in the prototyping of calorimeter detectors, in the testing of these detectors with particle beams, and in the construction of the final full size ATLAS components. Since liquid argon is very cold, about -188 degrees Celsius, the calorimeters must be enclosed in purpose-built cryostats. A critical component of such cryostats are its cryogenic feedthroughs, which allow nearly 200,000 electrical signals from the calorimeters to reach the outside world. Most of these feedthroughs were constructed in UVic between 1997 and 2002, with the support of an $4.0M NSERC Major Installation Grant. Members of the UVic team spent considerable time at CERN integrating these components on the final ATLAS detector.

From 2005 to 2009, the UVic-ATLAS group was heavily involved in the final preparation of the detector leading to first collisions. This commissioning work involved the testing of aspects of the ATLAS detector.  UVic scientists developped and maintained computer software and methods that are used to monitor the detector operations, and to ensure that the recorded data is of the highest quality. UVic scientists also developed strategies and software for the analysis of the collisions.

Since 2010, UVic scientists are actively analyzing the data collected at the LHC, and particlpated in the discovery of a Higgs boson.  Analyses involve Standard Model and Higgs boson measurements, and searches for new phenomena such as supersymmetric particles, or evidence for Dark Matter.  UVic scientists also contribute to the operation of the ATLAS detector, in particlular the operation of the liquid argon calorimetry and the development and operation of the ATLAS high level trigger, and to the upgrade of the ATLAS liquid argn calorimeter electronics and the new muon small wheel.

A Memorial Symposium in honour of our colleague Prof. Alan Astbury (1934-2014) was held at UVic the 27-28 of April 2015 and featured a public talk by the Director General of CERN, Dr Rolf Heuer; this talk was the first of the Astbury Public Lecture series.

The VISPA-ATLAS team
Faculty and Adjunct Faculty
Research Associates
  • Dr. Christopher Anelli
  • Dr. Kenji Hamano
  • Dr. Ellis Kay
  • Dr. Gerardo Vasquez
Research Personnel and affiliates
PhD Graduate Students
  • Evan Carlson
  • Charlie Chen
  • Justin Chiu
  • Meisam Ghasemi Bostanabad
  • Danika MacDonell
  • Kayla McLean
  • Juan Cristóbal Rivera
MSc Graduate Students
  • Luke Polson
  • Maheyer Shroff
  • Samantha Taylor
  • Benjamin Wright

Former UVic-ATLAS Research Associates
Name
Dates
Current (or post-UVic) Position

Dr. Emma Siân Kuwertz

2015-2018 CERN Fellow, Geneva

Dr. Monica Trovatelli

2015-2018 Industry, Vienna

Dr. Manuela Venturi

2014-2017 Consultant, Bain & Company, Milano

Dr. Frank Berghaus

2013-2014 Scientist, Cloud developer, UVic HEP
Dr. Florian Bernlochner 2011-2014 Professor at KIT, Karlsruhe, Germany
Dr. Margret Fincke-Keeler 1994-2014 Retired
Dr. Christopher Marino 2011-2014 Science Teacher, Memphis, TN
Dr. Vikas Bansal 2010-2013 Postdoc, PNNL, Richland, WA
Dr. Alex Martyniuk 2011-2013 Postdoc, UCL, London
Dr. Swagato Banerjee 2009-2011 Faculty, U of Louisville, KY
Dr. Mathieu Plamondon 2009-2011 Scientist, EMPA, Zürich area
Dr. Rolf Seuster 2004-2009 Scientist, HEPnet Manager, Victoria
Dr. Damir Lelas 2006-2008 Faculty, U of Split
Dr. Kai Voss 2004-2006 Space Industry, SpaceTech GmbH, Germany
Dr. Monika Wielers 2004 Research Scientist, RAL, Ditcot
Dr. Naoko Kanaya 2001-2003 Faculty, U of Tokyo
Former UVic-ATLAS Research Personnel and Affiliates
Name
Dates
Current (or post-UVic) Position

Paul Birney

until Feb 2018 Retired

Dr. Paul Poffenberger

until end of 2017 Retired
Roy Langstaff until end of 2016 Retired
Former UVic-ATLAS Ph.D. Students
Name
Dates
Current (or post-UVic) Position
Dr. Alison Elliot Ph.D. 2017 Research Assistant, QMUL, London
Dr. Ewan Hill Ph.D. 2017 Research Assistant, UBC, Vancouver
Dr. Tony Kwan Ph.D. 2017 Research Assistant, McGill, Montréal
Dr. Matthew Leblanc Ph.D. 2017 Research Assistant, UofArizona, Tucson
Dr. Claire David Ph.D. 2016 Research Assistant, DESY, Hamburg
Dr. James Pearce Ph.D. 2015 Data Scientist, Amazon 9
Dr. Eric Ouellette Ph.D. 2014 Actuarial Analyst, Morneau Shepell, NB
Dr. Frank Berghaus Ph.D. 2013 Scientist, Cloud developer, UVic HEP
Dr. Jean-Raphael Lessard Ph.D. 2012 Polar Asset Management Partners, Toronto
Dr. Lorraine Courneyea Ph.D. 2011 Medical Physicist, Sunnybrook, Toronto, and Clinical Assistant Professor at UofT
Dr. Tayfun Ince Ph.D. 2009 Research Assistant, MPI (CERN)
Dr. Daniel Vanderster Ph.D. 2008 CERN, IT Department
Dr. Matt Dobbs Ph.D. 2002 Faculty and CRC Chair, McGill
Dr. Dugan O'Neil Ph.D. 2000 Faculty, Simon Fraser U
Former UVic-ATLAS M.Sc. Students
Name
Dates
Current (or post-UVic) Position
Evan Carlson M.Sc. 2019 Ph.D. student, UVic
Zhelun Li M.Sc. 2019 Ph.D. student, McGill
Graeme Niedermayer M.Sc. 2017  
Justin Chiu M.Sc. 2016 Ph.D. student, UVic
Ryan Porter M.Sc. 2015 Ph.D. student, Cornell
Brock Moir M.Sc. 2014 Data Analyst, Yardi Energy
Dr. Tony Kwan M.Sc. 2012 Research Assistant, McGill, Montréal
Michael Jarrett M.Sc. 2011 Ph.D. student and RA, MRI Research, UBC
Dr. Ewan Hill M.Sc. 2011 Research Assistant, UBC, Vancouver
Dr. James Pearce M.Sc. 2011 Data Scientist, Amazon 9
Dr. Kuhan Wang M.Sc. 2011 Data Scientist, Gartner
Mark Baker M.Sc. 2009 Ph.D. student, UVic
Ryan Taylor M.Sc. 2009 Computing ATLAS Tier-2, UVic
Dr. Keith Edmonds M.Sc. 2007 Data Scientist, King, Stockholm
Tamara Hughes M.Sc. 2006 Independent business, Calgary
Warren Shaw M.Sc. 2006 Private sector research, Calgary
Dr. Tayfun Ince M.Sc. 2005 Research Assistant, MPI (CERN)
Dr. Dominique Fortin M.Sc. 2001 Medical Physics, UHN, Toronto
Dr. Shawn Bishop M.Sc. 1998 Faculty, Technische Universität München
Dr. Steve Robertson M.Sc. 1994 IPP Scientist and Faculty, McGill
Dr. John White M.Sc. 1993 Computing Scientist, Helsinki U
Former Undergraduate Students
  • Doris Noemi Rusu, summer 2019
  • Joseph Howie, spring and summer 2018
  • Tahya Weiss-Gibbons, fall 2017 and spring 2018
  • Chang Bi, summer 2017
  • Luke Polson, summer 2017 and summer 2019
  • Jodie Weldon, spring 2017
  • Trevor Lee, fall 2016
  • Lila Chergui, summer 2016
  • Sarah Eaton, spring 2016
  • Darryl Ring, spring 2016
  • Matthew Murray, summer 2015
  • Jannicke Pearkes, summer 2015
  • Danika MacDonell, spring and summer 2015
  • Justin Chiu, summer 2014
  • Kayla McLean, summer 2014
  • Jessica Strickland, summer 2014
  • Megan Tannock, summer 2014
  • Kristi Webb, summer 2014
  • Elizabeth Guthrie, summer 2013
  • Shane Sangha, summer 2013
  • Athreya Shankar, summer 2013
  • Brodyn Roberts, summer 2012
  • Maria Warren, summer 2011
  • Grace Dupuis, summer 2009
  • Robert Keyes, summer 2009
  • Alison Faulkner, fall 2008 and fall 2010
  • Clayton Lindsay, summer 2006
  • Graham Cox, summer 2005
  • Ian Gable, summer 2002 and summer 2003
  • Wendy Wiggins, spring and summer 2002
  • Guillaume Girard, summer 2001
  • Erica Muzzerall, summer 2001
  • John Lindner, fall 2000 and spring 2001
  • Robbie McDonald, summer 2000
  • Rob MacDonald, summer 1999
  • Sarah Groulx, summer 1998
  • Dugan O'Neil, summer 1992 and summer 1993
Selected UVic-ATLAS Presentations
Selected UVic-ATLAS Posters